An active matrix drive liquid crystal display panel includes a thin film transistor (hereinafter referred to as a “TFT”) substrate on which a TFT serving as a switching element is provided in each pixel, which is the smallest unit of an image.
The TFT substrate can be manufactured in the following manner, for example. An etch film and a photosensitive resin film are successively formed on a glass substrate. Thereafter, the photosensitive resin film is exposed to light via a photomask to form a resist pattern. The etch film exposed through the resist pattern is etched. This series of steps is repeatedly performed.
Incidentally, in the liquid crystal display panel including the TFT substrate, in order to reduce the manufacturing cost, techniques for manufacturing the TFT substrate, such as increasing the size of the glass substrate and reducing the number of the photomasks, have been conventionally proposed.
For example, PATENT DOCUMENT 1 describes a TFT substrate manufacturing method in which a photomask with a halftone pattern is used to form a resist pattern having three different thicknesses, thereby reducing the number of photomasks.
In a conventional TFT substrate manufacturing method employing a silicon semiconductor film, a silicon film serving as a semiconductor film and a conductive oxide film serving as a pixel electrode are separately formed. In recent years, a high-performance next-generation TFT which employs an oxide semiconductor film as a semiconductor film has been proposed.
For example, PATENT DOCUMENT 2 describes a TFT array in which pixel electrodes are formed of an oxide semiconductor film which forms TFTs, and a method for manufacturing the TFT array.
CITATION LIST
Patent Documents
PATENT DOCUMENT 1: Japanese Patent Publication No. 2000-164886
PATENT DOCUMENT 2: Japanese Patent Publication No. 2008-40343